After the coming out party that was last season, expecting him to come back to Earth would be extremely reasonable, akin to a rookie whom the rest of the league had finally gotten a winter to read the scouting report on. But R.A. Dickey is no rookie.

He is, despite his relatively brief time in the Majors, a mature pitcher. Having started his career as a power thrower who converted only because of a missing ligament in his arm, he has become adept at evolving to keep ahead of the hitters. He changes speeds, with knuckleballs that can vary within a 15-20 MPH range and throwing an occasional fastball that still peaks in the 80’s. Most important to his development is that he believes that he is still learning his pitch, that there are more changes he can make to improve his game. He feels that teams won’t have a full scouting report on him because he is not done writing it yet.

– Kieran Flemming, Mets Fever.

We know R.A. Dickey’s going to be awesome in 2011 because he’s presumably still going to be throwing knuckleballs and reading Faulkner and using big words in postgame interviews and everything else. And all those things are cool. But just how awesome can we expect R.A. Dickey to be?

Flemming argues that we shouldn’t expect a so-called “sophomore slump” from Dickey because he’s a mature pitcher willing to adjust his game, and perhaps that’s reasonable.

But will Dickey regress toward the mean? Was he perhaps the beneficiary of some good luck and did he pitch a bit above his head last season? It’s hard to say because Dickey is an outlier in so many ways. He has been getting progressively better since becoming a full-time knuckleballer, and he throws the hardest knuckleball I’ve ever seen — and mixes speeds with it.

Still, baseball is a game of perpetual adjustment. Certainly next season opposing hitters will have more experience against and more video of Dickey, and more knowledge of his tendencies, and Dickey will have to adjust in turn. But it doesn’t seem at all likely to me that he’ll continue pitching at the level he did last season.

Again, I have no solid evidence upon which to base that, just the knowledge that a 138 ERA+ at the Major League level is really, really difficult to sustain. For what it’s worth, Tim Wakefield threw 13 awesome starts for the Pirates when he first came up in 1992 and then enjoyed a career year when he first switched leagues in 1995, and both times he regressed thereafter.

That doesn’t mean Dickey won’t be useful or valuable or awesome, of course.

Although the analysis is complicated, the lessons it teaches us are straightforward. Streaky seasons undoubtedly exist, but it appears that there is no such thing as a streaky or unstreaky player. Rather, the truth seems to be that all players are streaky players. Being human, they have their ups and downs, and they are inherently streakier than random chance would dictate. They are not dice, and they are not random number generators. If Murray Chass ever read Fangraphs, I’m sure he’d be thrilled to hear that. But, again, there is no evidence whatsoever to suggest that a player who is especially streaky in one season will continue to be so in the next.

– Seth Samuels, Fangraphs.com.

The conclusion of Seth’s research I’ve mentioned here several times. Read the whole thing because the analysis is interesting and the scatterplot is money.